Reference signal resource location techniques in wireless communications

ABSTRACT

Methods, systems, and devices for wireless communication are described in which a number of reference signal processes may be configured for a number of slots in a radio frame, and a corresponding reference signal process for each slot may be based at least in part on a location of the slot within the radio frame and a number of configured reference signal processes. An indication may be provided to a user equipment (UE) in each slot that indicates a presence or absence of a reference signal transmission in the slot.

CROSS REFERENCES

The present Application for Patent is a Continuation of U.S. patentapplication Ser. No. 15/943,518 by Subramanian, et al., entitled“Reference Signal Resource Location Techniques in WirelessCommunications” filed Apr. 2, 2018, which claims priority to U.S.Provisional Patent Application No. 62/481,669 by Subramanian, et al.,entitled “Reference Signal Resource Location Techniques in WirelessCommunications,” filed Apr. 4, 2017, assigned to the assignee hereof.

BACKGROUND

The following relates generally to wireless communication, and morespecifically to reference signal resource location techniques inwireless communications.

Wireless communications systems are widely deployed to provide varioustypes of communication content such as voice, video, packet data,messaging, broadcast, and so on. These systems may be capable ofsupporting communication with multiple users by sharing the availablesystem resources (e.g., time, frequency, and power). Examples of suchmultiple-access systems include code division multiple access (CDMA)systems, time division multiple access (TDMA) systems, frequencydivision multiple access (FDMA) systems, and orthogonal frequencydivision multiple access (OFDMA) systems, (e.g., a Long Term Evolution(LTE) system, or a New Radio (NR) system). A wireless multiple-accesscommunications system may include a number of base stations or accessnetwork nodes, each simultaneously supporting communication for multiplecommunication devices, which may be otherwise known as user equipment(UE).

In some wireless systems, devices (e.g., base stations and UEs) maycommunicate using directional transmissions (e.g., beams), in whichbeamforming may be applied using multiple antenna elements to provide abeam in a particular direction. In some cases, a base station may beunaware of a particular location of a UE, such as when a gap incommunications occurs while a UE is moving. When a first device does notknow the direction in which to transmit to a second device, the firstdevice may transmit to the second device by sweeping through a set ofbeams focused in different directions, and transmitting a duplicativesignal or information on each of the beams. Alternatively, the firstdevice may transmit on one or a few beams, and the second device maysweep through a set of beams in an attempt to locate the beam or beamson which the first device is transmitting. In some cases, both the firstdevice and the second device may sweep through a set of beams totransmit and receive.

SUMMARY

The described techniques relate to improved methods, systems, devices,or apparatuses that support reference signal resource locationtechniques in wireless communications. In a wireless communicationssystem, such as a millimeter wave (mmW) system, a base station and auser equipment (UE) may utilize directional transmissions for referencesignal processes that may be used to find and maintain suitable beams toenable a communication link between the UE and the base station. In someexamples, the UE may configure a number of reference signal processesfor a number of slots in a radio frame and may, for each slot, identifya corresponding reference signal process of the configured referencesignal processes. In some cases, the corresponding reference signalprocess for each slot may be based at least in part on a location of theslot within the radio frame, a number of configured reference signalprocesses, or combinations thereof.

The UE may configure RF receive components for a slot based on theidentified reference signal process for the slot, and may monitor forcontrol information that indicates whether a reference signal istransmitted in the slot. If the control information indicates that areference signal is present in the slot, the UE may receive thereference signal based on the configured RF receive components. In someexamples, the control information may be an indication that istransmitted in downlink control information (DCI) associated with eachslot that indicates a presence or absence of a reference signaltransmission in the slot, thus allowing a base station to transmitnon-periodic reference signals (e.g., a semi-persistent or aperiodicCSI-RS) that may be received at the UE.

A method of wireless communication is described. The method may includeidentifying, for at least one of a plurality of slots, a correspondingreference signal process of a plurality of configured reference signalprocesses based at least in part on a location of the slot, wherein thecorresponding reference signal process indicates one or more beamformingparameters for a receive beam, receiving a control signal that indicatesa presence of a non-periodic reference signal in at least one of theplurality of slots, and receiving the reference signal in the at leastone of the plurality of slots based at least in part on the controlsignal and the beamforming parameters.

An apparatus for wireless communication is described. The apparatus mayinclude means for identifying, for at least one of a plurality of slots,a corresponding reference signal process of a plurality of configuredreference signal processes based at least in part on a location of theslot, wherein the corresponding reference signal process indicates oneor more beamforming parameters for a receive beam, means for receiving acontrol signal that indicates a presence of a non-periodic referencesignal in at least one of the plurality of slots, and means forreceiving the reference signal in the at least one of the plurality ofslots based at least in part on the control signal and the beamformingparameters.

Another apparatus for wireless communication is described. The apparatusmay include a processor, memory in electronic communication with theprocessor, and instructions stored in the memory. The instructions maybe operable to cause the processor to identify, for at least one of aplurality of slots, a corresponding reference signal process of aplurality of configured reference signal processes based at least inpart on a location of the slot, wherein the corresponding referencesignal process indicates one or more beamforming parameters for areceive beam, receive a control signal that indicates a presence of anon-periodic reference signal in at least one of the plurality of slots,and receive the reference signal in the at least one of the plurality ofslots based at least in part on the control signal and the beamformingparameters.

A non-transitory computer readable medium for wireless communication isdescribed. The non-transitory computer-readable medium may includeinstructions operable to cause a processor to identify, for at least oneof a plurality of slots, a corresponding reference signal process of aplurality of configured reference signal processes based at least inpart on a location of the slot, wherein the corresponding referencesignal process indicates one or more beamforming parameters for areceive beam, receive a control signal that indicates a presence of anon-periodic reference signal in at least one of the plurality of slots,and receive the reference signal in the at least one of the plurality ofslots based at least in part on the control signal and the beamformingparameters.

Some examples of the method, apparatus, and non-transitorycomputer-readable medium described above may further include processes,features, means, or instructions for transmitting, responsive toreceiving the non-periodic reference signal, a measurement report to abase station via a transmit beam of a beam pair link that includes thereceive beam. In some examples of the method, apparatus, andnon-transitory computer-readable medium described above, each of theplurality of configured reference signal processes includes one or moreof time resources or frequency resources configured for an associatedreference signal transmission. In some examples of the method,apparatus, and non-transitory computer-readable medium described above,the corresponding reference signal process of the plurality ofconfigured reference signal processes is identified based at least inpart on a slot index of the at least one of the plurality of slots. Insome examples of the method, apparatus, and non-transitorycomputer-readable medium described above, the corresponding referencesignal process of the plurality of configured reference signal processesmay be identified based at least in part on a slot index modulo thenumber of the plurality of configured reference signal processes. Insome examples of the method, apparatus, and non-transitorycomputer-readable medium described above, the control signal comprisesan indication in downlink control information (DCI) within the at leastone of the plurality of slots.

Some examples of the method, apparatus, and non-transitorycomputer-readable medium described above may further include processes,features, means, or instructions for receiving radio resource control(RRC) signaling with configuration information for the plurality ofconfigured reference signal processes.

A method of wireless communication is described. The method may includeconfiguring a user equipment (UE) with a plurality of reference signalprocesses for receiving and processing one or more reference signals tobe transmitted in one or more slots of a plurality of slots, each slotof the plurality of slots having a corresponding reference signalprocess of the plurality of reference signal processes based at least inpart on a location of the slot, transmitting a control signal toindicate a presence of a non-periodic reference signal in a first slotof the plurality of slots, and transmitting the non-periodic referencesignal in the first slot via a transmit beam of a plurality of transmitbeams.

An apparatus for wireless communication is described. The apparatus mayinclude means for configuring a user equipment (UE) with a plurality ofreference signal processes for receiving and processing one or morereference signals to be transmitted in one or more slots of a pluralityof slots, each slot of the plurality of slots having a correspondingreference signal process of the plurality of reference signal processesbased at least in part on a location of the slot, means for transmittinga control signal to indicate a presence of a non-periodic referencesignal in a first slot of the plurality of slots, and means fortransmitting the non-periodic reference signal in the first slot via atransmit beam of a plurality of transmit beams.

Another apparatus for wireless communication is described. The apparatusmay include a processor, memory in electronic communication with theprocessor, and instructions stored in the memory. The instructions maybe operable to cause the processor to configure a user equipment (UE)with a plurality of reference signal processes for receiving andprocessing one or more reference signals to be transmitted in one ormore slots of a plurality of slots, each slot of the plurality of slotshaving a corresponding reference signal process of the plurality ofreference signal processes based at least in part on a location of theslot, transmit a control signal to indicate a presence of a non-periodicreference signal in a first slot of the plurality of slots, and transmitthe non-periodic reference signal in the first slot via a transmit beamof a plurality of transmit beams.

A non-transitory computer readable medium for wireless communication isdescribed. The non-transitory computer-readable medium may includeinstructions operable to cause a processor to configure a user equipment(UE) with a plurality of reference signal processes for receiving andprocessing one or more reference signals to be transmitted in one ormore slots of a plurality of slots, each slot of the plurality of slotshaving a corresponding reference signal process of the plurality ofreference signal processes based at least in part on a location of theslot, transmit a control signal to indicate a presence of a non-periodicreference signal in a first slot of the plurality of slots, and transmitthe non-periodic reference signal in the first slot via a transmit beamof a plurality of transmit beams.

Some examples of the method, apparatus, and non-transitorycomputer-readable medium described above may further include processes,features, means, or instructions for receiving, responsive to thetransmitting the non-periodic reference signal, a measurement reportfrom the UE via a receive beam of a beam pair link that includes thetransmit beam. In some examples of the method, apparatus, andnon-transitory computer-readable medium described above, each of theplurality of reference signal processes includes one or more of timeresources or frequency resources configured for an associated referencesignal transmission. In some examples of the method, apparatus, andnon-transitory computer-readable medium described above, thecorresponding reference signal process of the plurality of configuredreference signal processes may be identified as a slot index modulo thenumber of the plurality of configured reference signal processes. Insome examples of the method, apparatus, and non-transitorycomputer-readable medium described above, the transmitting the controlsignal comprises setting an indicator in downlink control information(DCI) of the first slot to indicate the presence of absence of thereference signal in the first slot.

In some examples of the method, apparatus, and non-transitorycomputer-readable medium described above, the configuring comprisestransmitting radio resource control (RRC) signaling with configurationinformation for the plurality of reference signal processes to the UE.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 illustrates an example of a system for wireless communicationthat supports reference signal resource location techniques in wirelesscommunications in accordance with aspects of the present disclosure.

FIG. 2 illustrates an example of a wireless communication system thatsupports reference signal resource location techniques in wirelesscommunications in accordance with aspects of the present disclosure.

FIG. 3 illustrates an example of reference signal resources that supportreference signal resource location techniques in wireless communicationsin accordance with aspects of the present disclosure.

FIG. 4 illustrates an example of receive circuitry that supportsreference signal resource location techniques in wireless communicationsin accordance with aspects of the present disclosure.

FIG. 5 illustrates an example of a process flow that supports referencesignal resource location techniques in wireless communications inaccordance with aspects of the present disclosure.

FIGS. 6 through 8 show block diagrams of a device that supportsreference signal resource location techniques in wireless communicationsin accordance with aspects of the present disclosure.

FIG. 9 illustrates a block diagram of a system including a UE thatsupports reference signal resource location techniques in wirelesscommunications in accordance with aspects of the present disclosure.

FIGS. 10 through 12 show block diagrams of a device that supportsreference signal resource location techniques in wireless communicationsin accordance with aspects of the present disclosure.

FIG. 13 illustrates a block diagram of a system including a base stationthat supports reference signal resource location techniques in wirelesscommunications in accordance with aspects of the present disclosure.

FIGS. 14 through 15 illustrate methods for reference signal resourcelocation techniques in wireless communications in accordance withaspects of the present disclosure.

DETAILED DESCRIPTION

In a wireless communications system, such as millimeter wave (mmW) or anew radio (NR) system, a base station and a user equipment (UE) mayutilize directional beams for communications. In cases where a basestation does not know a particular direction of a UE, the base stationmay not know a directional beam that may be used for transmissions tothe UE. In such cases, the base station may transmit multipledirectional beams in a beam sweeping manner in multiple differentdirections in order to enhance the likelihood that such a UE willreceive the transmission. In some cases, beam sweeping may be used forreference signal processes that may be used to find and maintainsuitable beams to enable a communication link between the UE and thebase station.

Further, for a given link the UE may measure channel quality anddetermine, for example, the appropriate rank and precoding matrix. Insome examples, the base station may transmit a reference signal burst,such as a channel state information reference signal (CSI-RS) burst,which may be associated with sweeping or fixed base station transmissionbeams. To properly receive the transmission beams, the UE may usecorresponding receive beams, which may be configured by selecting anappropriate UE antenna subarray with an adequate receive-directivitypattern (e.g., according to an antenna weight vector). In some referencesignal processes, a base station may hold its beam constant over severalsymbols to enable the UE to try out different antenna subarrays,directivity patterns, or combinations thereof.

Depending on the reference signal process or resources used forreference signal transmissions, the UE may have to apply differentantenna subarrays with different directivity patterns for differentsymbols. In some cases, determining parameters to apply for receivingreference signal transmissions may be relatively computationallyintensive, and allowing a UE to prepare RF receive components for suchoperations in advance may allow for such processing to be performedunder more relaxed timelines and potentially at reduced processingpower. Further, a base station may benefit from flexibility indetermining which slots to use for reference signal processes. However,signaling the UE at the beginning of a slot through a controlinformation transmission that the reference signal process is to occurwithin the slot and using certain resources may require a relativelylarge amount of processing resources at the UE, which may result inincreased processor size and power consumption.

Various aspects of the present disclosure provide that a base stationmay configure a number of reference signal processes, and a particularprocess for a slot may be identified based on the number of configuredprocesses and a location of the slot within a radio frame. A UE may thuscompute receive parameters and configure receive hardware based on thelocation of the slot, the number of configured processes, orcombinations thereof. An indication may then be transmitted with a slottransmission that indicates whether the slot includes a reference signaltransmission, and the UE, based on the indication, may attempt toreceive the reference signal according to the configured process. Insome cases, a reference signal process number may be equal to the slotnumber within a radio frame modulo N, where N is larger than the numberof provisioned reference signal processes (e.g., N may be 4 or 8). Thisallows the UE to prepare the RF hardware for the appropriate sequence ofreceive-beams ahead of time, while also providing a base station withflexibility for scheduling non-periodic reference signals within slots.

Aspects of the disclosure are initially described in the context of awireless communications system. Aspects of the disclosure are furtherillustrated by and described with reference to apparatus diagrams,system diagrams, and flowcharts that relate to reference signal resourcelocation techniques in wireless communications.

FIG. 1 illustrates an example of a wireless communications system 100 inaccordance with various aspects of the present disclosure. The wirelesscommunications system 100 includes base stations 105, UEs 115, and acore network 130. In some examples, the wireless communications system100 may be an LTE (or LTE-Advanced) network, or an NR network. In somecases, wireless communications system 100 may support enhanced broadbandcommunications, ultra-reliable (i.e., mission critical) communications,low latency communications, and communications with low-cost andlow-complexity devices using beamformed transmission beams.

Base stations 105 may wirelessly communicate with UEs 115 via one ormore base station antennas. Each base station 105 may providecommunication coverage for a respective geographic coverage area 110.Communication links 125 shown in wireless communications system 100 mayinclude uplink transmissions from a UE 115 to a base station 105, ordownlink transmissions, from a base station 105 to a UE 115. Controlinformation and data may be multiplexed on an uplink channel or downlinkaccording to various techniques. Control information and data may bemultiplexed on a downlink channel, for example, using time divisionmultiplexing (TDM) techniques, frequency division multiplexing (FDM)techniques, or hybrid TDM-FDM techniques. In some examples, the controlinformation transmitted during a transmission time interval (TTI) of adownlink channel may be distributed between different control regions ina cascaded manner (e.g., between a common control region and one or moreUE-specific control regions).

UEs 115 may be dispersed throughout the wireless communications system100, and each UE 115 may be stationary or mobile. A UE 115 may also bereferred to as a mobile station, a subscriber station, a mobile unit, asubscriber unit, a wireless unit, a remote unit, a mobile device, awireless device, a wireless communications device, a remote device, amobile subscriber station, an access terminal, a mobile terminal, awireless terminal, a remote terminal, a handset, a user agent, a mobileclient, a client, or some other suitable terminology. A UE 115 may alsobe a cellular phone, a personal digital assistant (PDA), a wirelessmodem, a wireless communication device, a handheld device, a tabletcomputer, a laptop computer, a cordless phone, a personal electronicdevice, a handheld device, a personal computer, a wireless local loop(WLL) station, an Internet of things (IoT) device, an Internet ofEverything (IoE) device, a machine type communication (MTC) device, anappliance, an automobile, or the like.

Base stations 105 may communicate with the core network 130 and with oneanother. For example, base stations 105 may interface with the corenetwork 130 through backhaul links 132 (e.g., S1, etc.). Base stations105 may communicate with one another over backhaul links 134 (e.g., X2,etc.) either directly or indirectly (e.g., through core network 130).Base stations 105 may perform radio configuration and scheduling forcommunication with UEs 115, or may operate under the control of a basestation controller (not shown). In some examples, base stations 105 maybe macro cells, small cells, hot spots, or the like. Base stations 105may also be referred to as eNodeBs (eNBs) 105.

A base station 105 may be connected by an S1 interface to the corenetwork 130. The core network 130 may be an evolved packet core (EPC),which may include at least one mobility management entity (MME), atleast one serving gateway (S-GW), and at least one Packet Data Network(PDN) Gateway (P-GW). The MME may be the control node that processes thesignaling between the UE 115 and the EPC. All user internet protocol(IP) packets may be transferred through the S-GW, which itself may beconnected to the P-GW. The P-GW may provide IP address allocation aswell as other functions. The P-GW may be connected to the networkoperators IP services. The operators IP services may include theInternet, the Intranet, an IP Multimedia Subsystem (IMS), and aPacket-Switched Streaming Service (PSS).

Wireless communications system 100 may operate in an ultra highfrequency (UHF) frequency region using frequency bands from 700 MHz to2600 MHz (2.6 GHz), although in some cases WLAN networks may usefrequencies as high as 4 GHz. This region may also be known as thedecimeter band, since the wavelengths range from approximately onedecimeter to one meter in length. UHF waves may propagate mainly by lineof sight, and may be blocked by buildings and environmental features.However, the waves may penetrate walls sufficiently to provide serviceto UEs 115 located indoors. Transmission of UHF waves is characterizedby smaller antennas and shorter range (e.g., less than 100 km) comparedto transmission using the smaller frequencies (and longer waves) of thehigh frequency (HF) or very high frequency (VHF) portion of thespectrum. In some cases, wireless communications system 100 may alsoutilize extremely high frequency (EHF) portions of the spectrum (e.g.,from 30 GHz to 300 GHz). This region may also be known as the millimeterband, since the wavelengths range from approximately one millimeter toone centimeter in length. Thus, EHF antennas may be even smaller andmore closely spaced than UHF antennas. In some cases, this mayfacilitate use of antenna arrays within a UE 115 (e.g., for directionalbeamforming). However, EHF transmissions may be subject to even greateratmospheric attenuation and shorter range than UHF transmissions.

Thus, wireless communications system 100 may support millimeter wave(mmW) communications between UEs 115 and base stations 105. Devicesoperating in mmW or EHF bands may have multiple antennas to allowbeamforming. That is, a base station 105 may use multiple antennas orantenna arrays to conduct beamforming operations for directionalcommunications with a UE 115. Beamforming (which may also be referred toas spatial filtering or directional transmission) is a signal processingtechnique that may be used at a transmitter (e.g., a base station 105)to shape and/or steer an overall antenna beam, or directional beam, inthe direction of a target receiver (e.g., a UE 115). This may beachieved by combining elements in an antenna array in such a way thattransmitted signals at particular angles experience constructiveinterference while others experience destructive interference.

Multiple-input multiple-output (MIMO) wireless systems use atransmission scheme between a transmitter (e.g., a base station 105) anda receiver (e.g., a UE 115), where both transmitter and receiver areequipped with multiple antennas. Some portions of wirelesscommunications system 100 may use beamforming. For example, base station105 may have an antenna array with a number of rows and columns ofantenna ports that the base station 105 may use for beamforming in itscommunication with UE 115. Signals may be transmitted multiple times indifferent directions (e.g., each transmission may be beamformeddifferently). In some cases, reference signal processes (e.g., CSI-RSprocesses) may be configured in which a mmW receiver (e.g., a UE 115)may try multiple beams (e.g., antenna subarrays) while receiving thereference signals, and may use the multiple beams for measurements toestablish or maintain communication link 125.

In some cases, wireless communications system 100 may be a packet-basednetwork that operates according to a layered protocol stack. In the userplane, communications at the bearer or Packet Data Convergence Protocol(PDCP) layer may be IP-based. A Radio Link Control (RLC) layer may insome cases perform packet segmentation and reassembly to communicateover logical channels. A Medium Access Control (MAC) layer may performpriority handling and multiplexing of logical channels into transportchannels. The MAC layer may also use Hybrid ARQ (HARD) to provideretransmission at the MAC layer to improve link efficiency. In thecontrol plane, the Radio Resource Control (RRC) protocol layer mayprovide establishment, configuration, and maintenance of an RRCconnection between a UE 115 and a network device 105, or core network130 supporting radio bearers for user plane data. At the Physical (PHY)layer, transport channels may be mapped to physical channels.

Time intervals in LTE or NR may be expressed in multiples of a basictime unit (which may be a sampling period of T_(s)=1/30,720,000seconds). Time resources may be organized according to radio frames oflength of 10 ms (T_(f)=307200 T_(s)), which may be identified by asystem frame number (SFN) ranging from 0 to 1023. Each frame may includeten 1 ms subframes numbered from 0 to 9. A subframe may be furtherdivided into two 0.5 ms slots, each of which contains 6 or 7 modulationsymbol periods (depending on the length of the cyclic prefix prependedto each symbol). Excluding the cyclic prefix, each symbol contains 2048sample periods. In some cases the subframe may be the smallestscheduling unit, also known as a TTI. In other cases, a TTI may beshorter than a subframe or may be dynamically selected (e.g., in shortTTI bursts or in selected component carriers using short TTIs).

In some cases, wireless system 100 may utilize both licensed andunlicensed radio frequency spectrum bands. For example, wireless system100 may employ LTE License Assisted Access (LTE-LAA) or LTE Unlicensed(LTE U) radio access technology or NR technology in an unlicensed bandsuch as the 5 Ghz Industrial, Scientific, and Medical (ISM) band. Whenoperating in unlicensed radio frequency spectrum bands, wireless devicessuch as base stations 105 and UEs 115 may employ listen-before-talk(LBT) procedures to ensure the channel is clear before transmittingdata. In some cases, operations in unlicensed bands may be based on a CAconfiguration in conjunction with CCs operating in a licensed band.Operations in unlicensed spectrum may include downlink transmissions,uplink transmissions, or both. Duplexing in unlicensed spectrum may bebased on frequency division duplexing (FDD), time division duplexing(TDD) or a combination of both.

As indicated above, in some examples a UE 115 and a base station 105 mayuse directional beams for communications, and may use beam sweepingtechniques to find and maintain suitable beams to enable a communicationlink between the UE and the base station. In some cases, the basestation 105 may configure a number of reference signal processes, and aparticular process for a slot within a radio frame may be identifiedbased on the number of configured processes, a location of the slotwithin the radio frame, or combinations thereof. The UE 115 may thuscompute receive parameters and configure receive hardware based on thelocation of the slot and the number of configured processes. The basestation 105 may transmit an indication (e.g., in DCI in the slot) thatindicates whether the slot includes a reference signal transmission, andthe UE 115, based on the indication, may attempt to receive thereference signal according to the configured process.

FIG. 2 illustrates an example of a wireless communication system 200that supports reference signal resource location techniques in wirelesscommunications in accordance with various aspects of the presentdisclosure. Wireless communication system 200 includes a base station105-a and a UE 115-a, each of which may be an example of thecorresponding device described with reference to FIG. 1.

Wireless communication system 200 may operate in frequency ranges thatare associated with beamformed transmissions between base station 105-aand UE 115-a. For example, wireless communication system 200 may operateusing mmW frequency ranges. As a result, signal processing techniques,such as beamforming may be used to combine energy coherently andovercome path losses. By way of example, base station 105-a may containmultiple antennas. In some cases, each antenna may transmit aphase-shifted version of a signal such that the phase-shifted versionsconstructively interfere in certain regions and destructively interferein others. Weights may be applied to the various phase-shifted versions,e.g., in order to steer the transmissions in a desired direction. Suchtechniques (or similar techniques) may serve to increase the coveragearea 110-a of the base station 105-a or otherwise benefit the wirelesscommunication system 200.

Transmit beams 205-a and 205-b represent examples of beams over whichinformation may be transmitted. Accordingly, each transmit beam 205 maybe directed from base station 105-a toward a different region of thecoverage area 110-a and in some cases, two or more beams may overlap.Transmit beams 205-a and 205-b may be transmitted simultaneously or atdifferent times. In either case, a UE 115-a may be capable of receivingone or more transmit beams 205 via respective receive beams 210.

In one example, UE 115-a may form one or more receive beams 210. Similarto base station 105-a, UE 115-a may contain multiple antennas. In somecases, the receive beams 210 may receive a single transmit beam 205. Atransmit beam 205 and a corresponding receive beam 210 may in some casesbe referred to as a beam pair link 215. Various methods for identifyinga desired beam pair link 215 are considered within the scope of thepresent disclosure. For example, in some cases base station 105-a mayrepeat transmissions over multiple transmit beams 205 (e.g., in everydirection) and UE 115-a may report the strongest received beam (e.g.,without necessarily trying multiple receive beams 210). Additionally oralternatively, base station 105-a may transmit multiple transmit beams205 over a small angular region (e.g., to assist a UE 115-a infine-tuning the selected transmit beam 205). Further, in some cases,base station 105-a may repeat transmission of a single transmit beam(e.g., transmit beam 205-a) multiple times (e.g., to allow UE 115-a tocompare multiple receive beams 210).

In some examples, transmit beams 205 may carry downlink transmissionswhich may include CSI-RS 220, and different CSI-RS processes may beconfigured at different slots within a radio frame, thus providingmultiple transmission such as first CSI-RS transmission 220-a, secondCSI-RS transmission 220-b, and third CSI-RS transmission 220-c. Basestation 105-a may transmit to UE 115-a using multiple transmit beams205, and UE 115-a may use different antenna sub-arrays to create variousreceive beams 210. For instance, during a cell acquisition procedure,the UE 115-a may receive one or more transmit beams 205 using differentreceive beams 210 and may determine the transmit beam 205 and receivebeam 210 pairing that has the strongest signal (i.e., has the highestmeasured signal strength or highest signal to noise ratio (SNR), etc.).Throughout communications, the UE 115-a may reassess the transmit beamand receive beam pairing (e.g., which may be referred to as beammanagement).

As discussed above, the base station 105-a may configure a number ofreference signal processes. Each of the processes may be associatedwith, for example, a coarse beam search or fine tuning of a given beam(e.g., different processes for different antenna ports or combinationsof antenna ports may be performed concurrently). A particular processfor a slot may be identified based on the number of configured processesand a slot index (e.g., as the slot index modulo the number ofconfigured processes). The UE 115-a may thus compute receive parametersand configure receive hardware based on the location of the slot and thenumber of configured processes. The base station 105-a may transmit anindication (e.g., in DCI in the slot) that indicates whether the slotincludes a reference signal transmission (e.g., a CSI-RS 220transmission), and the UE 115, based on the indication, may attempt toreceive the reference signal according to the configured process.

FIG. 3 illustrates an example of reference signal resources 300 thatsupport reference signal resource location techniques in wirelesscommunications in accordance with various aspects of the presentdisclosure. In some examples, reference signal resources 300 may be usedto implement aspects of wireless communication system 100.

In the example, of FIG. 3, a number of slots 305 may be configured, andeach slot 305 may have an associated reference signal process, such as aCSI-RS process. In this example, four reference signal processes 310 maybe configured, which may include first reference signal process 310-a,second reference signal process 310-b, third reference signal process310-c, and fourth reference signal process 310-d. The particularreference signal process 310 for a slot 305 may be identified based onthe number of configured reference signal processes 310 and a locationof the slot 305 within a radio frame. For example, a radio frame mayinclude ten subframes, with each subframe having two slots 305, thusproviding 20 slots in a radio frame. Each slot 305 may be identified bya slot index (e.g., slot 0 through slot 19 in a radio frame). Further,each reference signal process 310 may have a process number. In someexamples, the particular reference signal process 310 for a slot 305 maybe determined based on the number of reference signal processes 310 anda slot 305 location within the radio frame. In some examples, thereference signal process 310 number for a slot 305 may be equal to theslot 305 number within the radio frame modulo N, where N is larger thanthe number of configured reference signal processes. In the example ofFIG. 3, N may be 4 and thus the first reference signal process 310-a maybe configured in every fourth slot 305. In other examples, the slotindex or subframe index used for determining the reference signalprocess 310 may be a system index such as a system frame number orsystem slot number (e.g., within a range of 0-1023, etc.). Thus, thereference signal processes may not have the same ordering betweendifferent frames.

An indication may then be transmitted in control information 315 withina slot 305 that indicates whether the slot 305 includes a referencesignal transmission for a reference signal process 310, and the UE,based on the indication, may attempt to receive the reference signalaccording to the configured process. This allows the UE to prepare theRF hardware for the appropriate sequence of receive-beams ahead of time,while also providing a base station with flexibility for schedulingreference signal processes within slots.

FIG. 4 illustrates an example of receive circuitry 400 that supportsreference signal resource location techniques in wireless communicationsin accordance with various aspects of the present disclosure. In someexamples, receive circuitry 400 may implement aspects of wirelesscommunication system 100.

Receive circuitry 400 may include a number of receive antennas 410 thatare each coupled with a low noise amplifier (LNA) 420 and a gain/phaseadjustment component 430. A receive beamforming controller 425 maycontrol the gain/phase adjustment components 430 based on a receive beamthat may be configured for a particular slot. Adder 440 may combine theoutputs of the gain/phase adjustment components 430, and output an addedsignal to mixer 450, downconverter 460, and analog-to-digital converter470.

In some examples, a UE may configure receive circuitry based on varioustransmission beam parameters of a transmission beam of interest.Depending on the reference signal process or resource set, the receivebeamforming controller 425 may apply different antenna subarrays withdifferent directivity patterns for different symbols, by adjusting LNAs420 and gain/phase adjust components 430 to achieve the desireddirectionality in the receive beam. In some cases, receive circuitry maybe implemented as analog circuitry in a UE receiver, which may requireadditional time prior to receiving a signal to properly set, which mayadd to the UE processing timeline constraints as discussed above. Inexamples where receive beamforming controller 425 may compute therelevant parameters prior to a slot, the UE may have additionalprocessing time, which may allow for a lower complexity processor orlower cost components and may reduce cost and power consumption.

FIG. 5 illustrates an example of a process flow 500 that supportsreference signal resource location techniques in wireless communicationsin accordance with various aspects of the present disclosure. In someexamples, process flow 500 may implement aspects of wirelesscommunication system 100. Process flow 500 includes a UE 115-b and basestation 105-b, each of which may be an example of the correspondingdevice described above with reference to FIGS. 1 and 2.

At 505, base station 105-b and UE 115-b may establish a communicationlink (e.g., which may be an example of a communication link 125 asdescribed with reference to FIG. 1). For example, the communication linkat 505 may support beamformed communications. In some cases, a beam pairlink may be established using a beam sweep procedure in which the basestation 105-b may repeat transmissions over multiple transmit beams andUE 115-b may report the strongest received beam. Additionally oralternatively, base station 105-b may transmit multiple transmit beamsover a small angular region to assist UE 115-b in fine-tuning theselected transmit beam.

At 510, base station 105-b may configure reference signal processes. Insome cases, the reference signal processes may include a number ofprocesses, and one of the processes may be selected for a particularslot based on one of more of the number of processes and a location ofthe slot (e.g., as the slot index modulo the number of processes, etc.).In some cases, the processes may include time resources for referencesignal transmissions, frequency resources for reference signaltransmissions, of combinations thereof. In some cases, the referencesignal processes may also include tuning parameters that may allow finetuning for transmission beams. The base station 105-b may transmitconfiguration information 515 to UE 115-b, which may include theconfigured reference signal processes.

At 520, the UE 115-b may identify reference signal processes forreceiving reference signals. Such identification may include identifyingtime resources, frequency resources, or combinations thereof, which maybe identified separately for different slots within a radio frame, basedon one of more of the number of reference signal processes and alocation of the particular slot within the radio frame. In some cases, areference signal process number may be equal to the slot number within aradio frame modulo N, where N is larger than the number of provisionedreference signal processes (e.g., N may be 4 or 8). This allows the UE115-b to prepare the RF hardware for the appropriate sequence ofreceive-beams ahead of time, while also providing a base station withflexibility for scheduling non-periodic reference signals within slots.

At 530, the UE 115-b may compute receive parameters based on thereference signal processes and the slot locations. In some cases, theparameters may be computed for which antennas of antenna sub-array atthe UE 115-b are to be used, as well as weights and phase shifts thatare to be applied at each antenna.

At 535, the UE 115-b may configure receive circuitry. The configurationof the receive circuitry may include configuring various analog RFcomponents according to the receive parameters that were computed. Insome examples, a receive beamforming controller at UE 115-b may applydifferent antenna subarrays with different directivity patterns fordifferent symbols, by adjusting LNAs and gain/phase adjust components toachieve the desired directionality in the receive beam.

The base station 105-b, at 525, may determine slots for reference signaltransmissions. In some cases, the base station 105-b may determine slotsfor reference signal processes based on various factors, such as channelquality aspects, timing since prior reference signal processes, or oneor more other factors. In the event that the base station 105-bdetermines that a reference signal process is to be configured for aslot, the base station 105-b may, for example, set a flag to indicatethe presence or absence of a reference signal transmission in the slot.Such an indication 540 may be transmitted to the UE 115-b followed by areference signal transmission 545 in the resources that were configuredfor the slot. Such determination at the base station 105-b may allow thebase station to schedule non-periodic reference signal transmissions, asperiodic reference signal transmissions would be preconfigured andtransmitted without an indication of the presence of absence of areference signal transmission.

The UE 115-b, at 550 may perform reference signal processing, and insome cases may transmit a measurement report 555 to the base station105-b. The reference signal processing may include channel statemeasurements, which may include energy measurements for a referencesignal, interference and noise measurements, or any combination thereof.

FIG. 6 shows a block diagram 600 of a wireless device 605 that supportsreference signal resource location techniques in wireless communicationsin accordance with aspects of the present disclosure. Wireless device605 may be an example of aspects of a user equipment (UE) 115 asdescribed herein. Wireless device 605 may include receiver 610, UEreference signal manager 615, and transmitter 620. Wireless device 605may also include a processor. Each of these components may be incommunication with one another (e.g., via one or more buses).

Receiver 610 may receive information such as packets, user data, orcontrol information associated with various information channels (e.g.,control channels, data channels, and information related to referencesignal resource location techniques in wireless communications, etc.).Information may be passed on to other components of the device. Thereceiver 610 may be an example of aspects of the transceiver 935described with reference to FIG. 9. The receiver 610 may utilize asingle antenna or a set of antennas.

UE reference signal manager 615 may be an example of aspects of the UEreference signal manager 915 described with reference to FIG. 9.

UE reference signal manager 615 and/or at least some of its varioussub-components may be implemented in hardware, software executed by aprocessor, firmware, or any combination thereof. If implemented insoftware executed by a processor, the functions of the UE referencesignal manager 615 and/or at least some of its various sub-componentsmay be executed by a general-purpose processor, a digital signalprocessor (DSP), an application-specific integrated circuit (ASIC), anfield-programmable gate array (FPGA) or other programmable logic device,discrete gate or transistor logic, discrete hardware components, or anycombination thereof designed to perform the functions described in thepresent disclosure. The UE reference signal manager 615 and/or at leastsome of its various sub-components may be physically located at variouspositions, including being distributed such that portions of functionsare implemented at different physical locations by one or more physicaldevices. In some examples, UE reference signal manager 615 and/or atleast some of its various sub-components may be a separate and distinctcomponent in accordance with various aspects of the present disclosure.In other examples, UE reference signal manager 615 and/or at least someof its various sub-components may be combined with one or more otherhardware components, including but not limited to an I/O component, atransceiver, a network server, another computing device, one or moreother components described in the present disclosure, or a combinationthereof in accordance with various aspects of the present disclosure.

UE reference signal manager 615 may identify, for at least one of a setof slots, a corresponding reference signal process of a set ofconfigured reference signal processes based on one or more of a locationof the slot and a number of the set of configured reference signalprocesses, configure receive circuitry to receive a reference signaltransmission over a receive beam in the at least one of the set of slotsbased on the corresponding reference signal process, receive a controlsignal that indicates a presence of the reference signal transmissionwithin the at least one of the set of slots, and receive the referencesignal in the at least one of the set of slots based on the controlsignal and the configured receive circuitry.

Transmitter 620 may transmit signals generated by other components ofthe device. In some examples, the transmitter 620 may be collocated witha receiver 610 in a transceiver module. For example, the transmitter 620may be an example of aspects of the transceiver 935 described withreference to FIG. 9. The transmitter 620 may utilize a single antenna ora set of antennas.

FIG. 7 shows a block diagram 700 of a wireless device 705 that supportsreference signal resource location techniques in wireless communicationsin accordance with aspects of the present disclosure. Wireless device705 may be an example of aspects of a wireless device 605 or a UE 115 asdescribed with reference to FIG. 6. Wireless device 705 may includereceiver 710, UE reference signal manager 715, and transmitter 720.Wireless device 705 may also include a processor. Each of thesecomponents may be in communication with one another (e.g., via one ormore buses).

Receiver 710 may receive information such as packets, user data, orcontrol information associated with various information channels (e.g.,control channels, data channels, and information related to referencesignal resource location techniques in wireless communications, etc.).Information may be passed on to other components of the device. Thereceiver 710 may be an example of aspects of the transceiver 935described with reference to FIG. 9. The receiver 710 may utilize asingle antenna or a set of antennas.

UE reference signal manager 715 may be an example of aspects of the UEreference signal manager 915 described with reference to FIG. 9. UEreference signal manager 715 may also include reference signal processmanager 725, receive beamforming controller 730, control signalidentification component 735, and receive beam manager 740.

Reference signal process manager 725 may identify, for at least one of aset of slots, a corresponding reference signal process of a set ofconfigured reference signal processes based on one or more of a locationof the slot and a number of the set of configured reference signalprocesses. In some cases, reference signal process manager 725 mayreceive radio resource control (RRC) signaling with configurationinformation for the set of configured reference signal processes. Insome cases, each of the set of configured reference signal processesincludes one or more of time resources or frequency resources configuredfor an associated reference signal transmission.

Receive beamforming controller 730 may configure receive circuitry toreceive a reference signal transmission over a receive beam in the atleast one of the set of slots based on the corresponding referencesignal process. For example, depending on the reference signal processor resource set, the receive beamforming controller 730 may applydifferent antenna subarrays with different directivity patterns fordifferent symbols, by adjusting LNAs and gain/phase adjust components toachieve the desired directionality in the receive beam. In some cases,receive circuitry may be implemented as analog circuitry in a UEreceiver, which may require additional time prior to receiving a signalto properly set, which may add to the UE processing timeline constraintsas discussed above. In examples where receive beamforming controller 730may compute the relevant parameters prior to a slot, the UE may haveadditional processing time.

Control signal identification component 735 may receive a control signalthat indicates a presence of the reference signal transmission withinthe at least one of the set of slots. In some cases, the control signalincludes an indication in downlink control information (DCI) within theat least one of the set of slots.

Receive beam manager 740 may receive the reference signal in the atleast one of the set of slots based on the control signal and theconfigured receive circuitry. The received reference signal may beprocessed to perform channel state measurements, which may includeenergy measurements for a reference signal, interference and noisemeasurements, or any combination thereof.

Transmitter 720 may transmit signals generated by other components ofthe device. In some examples, the transmitter 720 may be collocated witha receiver 710 in a transceiver module. For example, the transmitter 720may be an example of aspects of the transceiver 935 described withreference to FIG. 9. The transmitter 720 may utilize a single antenna ora set of antennas.

FIG. 8 shows a block diagram 800 of a UE reference signal manager 815that supports reference signal resource location techniques in wirelesscommunications in accordance with aspects of the present disclosure. TheUE reference signal manager 815 may be an example of aspects of a UEreference signal manager 615, a UE reference signal manager 715, or a UEreference signal manager 915 described with reference to FIGS. 6, 7, and9. The UE reference signal manager 815 may include reference signalprocess manager 820, receive beamforming controller 825, control signalidentification component 830, receive beam manager 835, and processidentification component 840. Each of these modules may communicate,directly or indirectly, with one another (e.g., via one or more buses).

Reference signal process manager 820 may identify, for at least one of aset of slots, a corresponding reference signal process of a set ofconfigured reference signal processes based on one or more of a locationof the slot and a number of the set of configured reference signalprocesses. Reference signal process manager 820 may also receive RRCsignaling with configuration information for the set of configuredreference signal processes. In some cases, each of the set of configuredreference signal processes includes one or more of time resources orfrequency resources configured for an associated reference signaltransmission.

Receive beamforming controller 825 may configure receive circuitry toreceive a reference signal transmission over a receive beam in the atleast one of the set of slots based on the corresponding referencesignal process. For example, depending on the reference signal processor resource set, the receive beamforming controller 825 may applydifferent antenna subarrays with different directivity patterns fordifferent symbols, by adjusting LNAs and gain/phase adjust components toachieve the desired directionality in the receive beam. In some cases,receive circuitry may be implemented as analog circuitry in a UEreceiver, which may require additional time prior to receiving a signalto properly set, which may add to the UE processing timeline constraintsas discussed above. In examples where receive beamforming controller 825may compute the relevant parameters prior to a slot, the UE may haveadditional processing time.

Control signal identification component 830 may receive a control signalthat indicates a presence of the reference signal transmission withinthe at least one of the set of slots. In some cases, the control signalincludes an indication in DCI within the at least one of the set ofslots.

Receive beam manager 835 may receive the reference signal in the atleast one of the set of slots based on the control signal and theconfigured receive circuitry. The received reference signal may beprocessed to perform channel state measurements, which may includeenergy measurements for a reference signal, interference and noisemeasurements, or any combination thereof.

Process identification component 840 may identify reference signalprocesses. In some cases, the corresponding reference signal process ofthe set of configured reference signal processes is identified as a slotindex modulo the number of the set of configured reference signalprocesses.

FIG. 9 shows a diagram of a system 900 including a device 905 thatsupports reference signal resource location techniques in wirelesscommunications in accordance with aspects of the present disclosure.Device 905 may be an example of or include the components of wirelessdevice 605, wireless device 705, or a UE 115 as described above, e.g.,with reference to FIGS. 6 and 7. Device 905 may include components forbi-directional voice and data communications including components fortransmitting and receiving communications, including UE reference signalmanager 915, processor 920, memory 925, software 930, transceiver 935,antenna 940, and I/O controller 945. These components may be inelectronic communication via one or more buses (e.g., bus 910). Device905 may communicate wirelessly with one or more base stations 105.

Processor 920 may include an intelligent hardware device, (e.g., ageneral-purpose processor, a DSP, a central processing unit (CPU), amicrocontroller, an ASIC, an FPGA, a programmable logic device, adiscrete gate or transistor logic component, a discrete hardwarecomponent, or any combination thereof). In some cases, processor 920 maybe configured to operate a memory array using a memory controller. Inother cases, a memory controller may be integrated into processor 920.Processor 920 may be configured to execute computer-readableinstructions stored in a memory to perform various functions (e.g.,functions or tasks supporting reference signal resource locationtechniques in wireless communications).

Memory 925 may include random access memory (RAM) and read only memory(ROM). The memory 925 may store computer-readable, computer-executablesoftware 930 including instructions that, when executed, cause theprocessor to perform various functions described herein. In some cases,the memory 925 may contain, among other things, a basic input/outputsystem (BIOS) which may control basic hardware and/or software operationsuch as the interaction with peripheral components or devices.

Software 930 may include code to implement aspects of the presentdisclosure, including code to support reference signal resource locationtechniques in wireless communications. Software 930 may be stored in anon-transitory computer-readable medium such as system memory or othermemory. In some cases, the software 930 may not be directly executableby the processor but may cause a computer (e.g., when compiled andexecuted) to perform functions described herein.

Transceiver 935 may communicate bi-directionally, via one or moreantennas, wired, or wireless links as described above. For example, thetransceiver 935 may represent a wireless transceiver and may communicatebi-directionally with another wireless transceiver. The transceiver 935may also include a modem to modulate the packets and provide themodulated packets to the antennas for transmission, and to demodulatepackets received from the antennas.

In some cases, the wireless device may include a single antenna 940.However, in some cases the device may have more than one antenna 940,which may be capable of concurrently transmitting or receiving multiplewireless transmissions.

I/O controller 945 may manage input and output signals for device 905.I/O controller 945 may also manage peripherals not integrated intodevice 905. In some cases, I/O controller 945 may represent a physicalconnection or port to an external peripheral. In some cases, I/Ocontroller 945 may utilize an operating system such as iOS®, ANDROID®,MS-DOS®, MS-WINDOWS®, OS/2®, UNIX®, LINUX®, or another known operatingsystem. In other cases, I/O controller 945 may represent or interactwith a modem, a keyboard, a mouse, a touchscreen, or a similar device.In some cases, I/O controller 945 may be implemented as part of aprocessor. In some cases, a user may interact with device 905 via I/Ocontroller 945 or via hardware components controlled by I/O controller945.

FIG. 10 shows a block diagram 1000 of a wireless device 1005 thatsupports reference signal resource location techniques in wirelesscommunications in accordance with aspects of the present disclosure.Wireless device 1005 may be an example of aspects of a base station 105as described herein. Wireless device 1005 may include receiver 1010,base station reference signal manager 1015, and transmitter 1020.Wireless device 1005 may also include a processor. Each of thesecomponents may be in communication with one another (e.g., via one ormore buses).

Receiver 1010 may receive information such as packets, user data, orcontrol information associated with various information channels (e.g.,control channels, data channels, and information related to referencesignal resource location techniques in wireless communications, etc.).Information may be passed on to other components of the device. Thereceiver 1010 may be an example of aspects of the transceiver 1335described with reference to FIG. 13. The receiver 1010 may utilize asingle antenna or a set of antennas.

Base station reference signal manager 1015 may be an example of aspectsof the base station reference signal manager 1315 described withreference to FIG. 13.

Base station reference signal manager 1015 and/or at least some of itsvarious sub-components may be implemented in hardware, software executedby a processor, firmware, or any combination thereof. If implemented insoftware executed by a processor, the functions of the base stationreference signal manager 1015 and/or at least some of its varioussub-components may be executed by a general-purpose processor, a DSP, anASIC, an FPGA or other programmable logic device, discrete gate ortransistor logic, discrete hardware components, or any combinationthereof designed to perform the functions described in the presentdisclosure. The base station reference signal manager 1015 and/or atleast some of its various sub-components may be physically located atvarious positions, including being distributed such that portions offunctions are implemented at different physical locations by one or morephysical devices. In some examples, base station reference signalmanager 1015 and/or at least some of its various sub-components may be aseparate and distinct component in accordance with various aspects ofthe present disclosure. In other examples, base station reference signalmanager 1015 and/or at least some of its various sub-components may becombined with one or more other hardware components, including but notlimited to an I/O component, a transceiver, a network server, anothercomputing device, one or more other components described in the presentdisclosure, or a combination thereof in accordance with various aspectsof the present disclosure.

Base station reference signal manager 1015 may configure a UE with a setof reference signal processes for receiving and processing one or morereference signals to be transmitted in one or more slots of a set ofslots, each slot of the set of slots having a corresponding referencesignal process of the set of reference signal processes based on one ormore of a location of the slot and a number of the set of configuredreference signal processes, determine that a non-periodic referencesignal is to be transmitted via a transmit beam in a first slot of theset of slots, transmit a control signal to indicate a presence of thereference signal in the first slot, and transmit the reference signal inthe first slot via the transmit beam.

Transmitter 1020 may transmit signals generated by other components ofthe device. In some examples, the transmitter 1020 may be collocatedwith a receiver 1010 in a transceiver module. For example, thetransmitter 1020 may be an example of aspects of the transceiver 1335described with reference to FIG. 13. The transmitter 1020 may utilize asingle antenna or a set of antennas.

FIG. 11 shows a block diagram 1100 of a wireless device 1105 thatsupports reference signal resource location techniques in wirelesscommunications in accordance with aspects of the present disclosure.Wireless device 1105 may be an example of aspects of a wireless device1005 or a base station 105 as described with reference to FIG. 10.Wireless device 1105 may include receiver 1110, base station referencesignal manager 1115, and transmitter 1120. Wireless device 1105 may alsoinclude a processor. Each of these components may be in communicationwith one another (e.g., via one or more buses).

Receiver 1110 may receive information such as packets, user data, orcontrol information associated with various information channels (e.g.,control channels, data channels, and information related to referencesignal resource location techniques in wireless communications, etc.).Information may be passed on to other components of the device. Thereceiver 1110 may be an example of aspects of the transceiver 1335described with reference to FIG. 13. The receiver 1110 may utilize asingle antenna or a set of antennas.

Base station reference signal manager 1115 may be an example of aspectsof the base station reference signal manager 1315 described withreference to FIG. 13.

Base station reference signal manager 1115 may also include referencesignal process manager 1125, resource allocation component 1130, controlsignal identification component 1135, and transmission beam manager1140.

Reference signal process manager 1125 may configure a UE with a set ofreference signal processes for receiving and processing one or morereference signals to be transmitted in one or more slots of a set ofslots, each slot of the set of slots having a corresponding referencesignal process of the set of reference signal processes based on one ormore of a location of the slot and a number of the set of configuredreference signal processes. In some cases, each of the set of referencesignal processes includes one or more of time resources or frequencyresources configured for an associated reference signal transmission. Insome cases, the configuring includes transmitting RRC signaling withconfiguration information for the set of reference signal processes tothe UE.

Resource allocation component 1130 may determine that a reference signalis to be transmitted in a first slot of the set of slots. In some cases,resource allocation component 1130 may determine slots for referencesignal processes based on various factors, such as channel qualityaspects, timing since prior reference signal processes, or one or moreother factors. Control signal identification component 1135 may transmita control signal in the first slot to indicate a presence of thereference signal in the first slot. In some cases, the transmitting thecontrol signal includes setting an indicator in DCI of the first slot toindicate the presence or absence of the reference signal in the firstslot. Transmission beam manager 1140 may transmit the reference signalin the first slot.

Transmitter 1120 may transmit signals generated by other components ofthe device. In some examples, the transmitter 1120 may be collocatedwith a receiver 1110 in a transceiver module. For example, thetransmitter 1120 may be an example of aspects of the transceiver 1335described with reference to FIG. 13. The transmitter 1120 may utilize asingle antenna or a set of antennas.

FIG. 12 shows a block diagram 1200 of a base station reference signalmanager 1215 that supports reference signal resource location techniquesin wireless communications in accordance with aspects of the presentdisclosure. The base station reference signal manager 1215 may be anexample of aspects of a base station reference signal manager 1315described with reference to FIGS. 10, 11, and 13. The base stationreference signal manager 1215 may include reference signal processmanager 1220, resource allocation component 1225, control signalidentification component 1230, transmission beam manager 1235, andprocess identification component 1240. Each of these modules maycommunicate, directly or indirectly, with one another (e.g., via one ormore buses).

Reference signal process manager 1220 may configure a UE with a set ofreference signal processes for receiving and processing one or morereference signals to be transmitted in one or more slots of a set ofslots, each slot of the set of slots having a corresponding referencesignal process of the set of reference signal processes based on alocation of the slot and a number of the set of configured referencesignal processes. In some cases, each of the set of reference signalprocesses includes one or more of time resources or frequency resourcesconfigured for an associated reference signal transmission. In somecases, the configuring includes transmitting RRC signaling withconfiguration information for the set of reference signal processes tothe UE.

Resource allocation component 1225 may determine that a reference signalis to be transmitted in a first slot of the set of slots. In some cases,resource allocation component 1130 may determine slots for referencesignal processes based on various factors, such as channel qualityaspects, timing since prior reference signal processes, or one or moreother factors. Control signal identification component 1230 may transmita control signal in the first slot to indicate a presence of thereference signal in the first slot. In some cases, the transmitting thecontrol signal includes setting an indicator in DCI of the first slot toindicate the presence or absence of the reference signal in the firstslot. Transmission beam manager 1235 may transmit the reference signalin the first slot.

Process identification component 1240 may identify reference signalprocesses. In some cases, the corresponding reference signal process ofthe set of configured reference signal processes is identified as a slotindex modulo the number of the set of configured reference signalprocesses.

FIG. 13 shows a diagram of a system 1300 including a device 1305 thatsupports reference signal resource location techniques in wirelesscommunications in accordance with aspects of the present disclosure.Device 1305 may be an example of or include the components of basestation 105 as described above, e.g., with reference to FIG. 1. Device1305 may include components for bi-directional voice and datacommunications including components for transmitting and receivingcommunications, including base station reference signal manager 1315,processor 1320, memory 1325, software 1330, transceiver 1335, antenna1340, network communications manager 1345, and inter-stationcommunications manager 1350. These components may be in electroniccommunication via one or more buses (e.g., bus 1310). Device 1305 maycommunicate wirelessly with one or more UEs 115.

Processor 1320 may include an intelligent hardware device, (e.g., ageneral-purpose processor, a DSP, a CPU, a microcontroller, an ASIC, anFPGA, a programmable logic device, a discrete gate or transistor logiccomponent, a discrete hardware component, or any combination thereof).In some cases, processor 1320 may be configured to operate a memoryarray using a memory controller. In other cases, a memory controller maybe integrated into processor 1320. Processor 1320 may be configured toexecute computer-readable instructions stored in a memory to performvarious functions (e.g., functions or tasks supporting reference signalresource location techniques in wireless communications).

Memory 1325 may include RAM and ROM. The memory 1325 may storecomputer-readable, computer-executable software 1330 includinginstructions that, when executed, cause the processor to perform variousfunctions described herein. In some cases, the memory 1325 may contain,among other things, a BIOS which may control basic hardware and/orsoftware operation such as the interaction with peripheral components ordevices.

Software 1330 may include code to implement aspects of the presentdisclosure, including code to support reference signal resource locationtechniques in wireless communications. Software 1330 may be stored in anon-transitory computer-readable medium such as system memory or othermemory. In some cases, the software 1330 may not be directly executableby the processor but may cause a computer (e.g., when compiled andexecuted) to perform functions described herein.

Transceiver 1335 may communicate bi-directionally, via one or moreantennas, wired, or wireless links as described above. For example, thetransceiver 1335 may represent a wireless transceiver and maycommunicate bi-directionally with another wireless transceiver. Thetransceiver 1335 may also include a modem to modulate the packets andprovide the modulated packets to the antennas for transmission, and todemodulate packets received from the antennas.

In some cases, the wireless device may include a single antenna 1340.However, in some cases the device may have more than one antenna 1340,which may be capable of concurrently transmitting or receiving multiplewireless transmissions.

Network communications manager 1345 may manage communications with thecore network (e.g., via one or more wired backhaul links). For example,the network communications manager 1345 may manage the transfer of datacommunications for client devices, such as one or more UEs 115.

Inter-station communications manager 1350 may manage communications withother base station 105, and may include a controller or scheduler forcontrolling communications with UEs 115 in cooperation with other basestations 105. For example, the inter-station communications manager 1350may coordinate scheduling for transmissions to UEs 115 for variousinterference mitigation techniques such as beamforming or jointtransmission. In some examples, inter-station communications manager1350 may provide an X2 interface within an Long Term Evolution(LTE)/LTE-A wireless communication network technology to providecommunication between base stations 105.

FIG. 14 shows a flowchart illustrating a method 1400 for referencesignal resource location techniques in wireless communications inaccordance with aspects of the present disclosure. The operations ofmethod 1400 may be implemented by a UE 115 or its components asdescribed herein. For example, the operations of method 1400 may beperformed by a UE reference signal manager as described with referenceto FIGS. 6 through 9. In some examples, a UE 115 may execute a set ofcodes to control the functional elements of the device to perform thefunctions described below. Additionally or alternatively, the UE 115 mayperform aspects of the functions described below using special-purposehardware.

At optional block 1405 the UE 115 may receive radio resource control(RRC) signaling with configuration information for the plurality ofconfigured reference signal processes. The operations of block 1405 maybe performed according to the methods described herein. In certainexamples, aspects of the operations of block 1405 may be performed by areference signal process manager as described with reference to FIGS. 6through 9. In some cases, the RRC signaling may provide a set ofavailable reference signal processes that may be used for referencesignal monitoring and related reporting at the UE.

At block 1410 the UE 115 may identify, for at least one of a pluralityof slots, a corresponding reference signal process of a plurality ofconfigured reference signal processes based at least in part on alocation of the slot. The operations of block 1410 may be performedaccording to the methods described herein. In certain examples, aspectsof the operations of block 1410 may be performed by a reference signalprocess manager as described with reference to FIGS. 6 through 9. Suchidentification may include identifying time resources, frequencyresources, or combinations thereof, which may be identified separatelyfor different slots within a radio frame, based on the number ofreference signal processes and a location of the particular slot withinthe radio frame. In some cases, a reference signal process number may beequal to the slot number within a radio frame modulo N, where N islarger than the number of provisioned reference signal processes (e.g.,N may be 4 or 8). This allows the UE to prepare the RF hardware for theappropriate sequence of receive-beams ahead of time, while alsoproviding a base station with flexibility for scheduling non-periodicreference signals within slots.

At block 1415 the UE 115 may configure receive circuitry to receive areference signal transmission over a receive beam in the at least one ofthe plurality of slots based at least in part on the correspondingreference signal process. The operations of block 1415 may be performedaccording to the methods described herein. In certain examples, aspectsof the operations of block 1415 may be performed by a receivebeamforming controller as described with reference to FIGS. 6 through 9.The configuration of the receive circuitry may include configuringvarious analog RF components according to the receive parameters thatwere computed. In some examples, a receive beamforming controller at UEmay apply different antenna subarrays with different directivitypatterns for different symbols, by adjusting LNAs and gain/phase adjustcomponents to achieve the desired directionality in the receive beam.

At block 1420 the UE 115 may receive a control signal that indicates apresence of a non-periodic reference signal in at least one of theplurality of slots. The operations of block 1420 may be performedaccording to the methods described herein. In certain examples, aspectsof the operations of block 1420 may be performed by a control signalidentification component as described with reference to FIGS. 6 through9. Such an indication may indicate the presence or absence of areference signal in the slot, and the reference process may bedetermined based on the configured reference signal processes (e.g.,based on a slot number of the slot). Such an indication may allow thebase station to schedule non-periodic reference signal transmissions.

At block 1425 the UE 115 may receive the reference signal in the atleast one of the plurality of slots based at least in part on thecontrol signal and the configured receive circuitry. The operations ofblock 1425 may be performed according to the methods described herein.In certain examples, aspects of the operations of block 1425 may beperformed by a receive beam manager as described with reference to FIGS.6 through 9. The UE, as part of receiving the reference signal mayperform reference signal processing such as channel state measurements,which may include energy measurements for a reference signal,interference and noise measurements, or any combination thereof.

At optional block 1430 the UE 115 may transmit, responsive to receivingthe non-periodic reference signal, a measurement report to a basestation via a transmit beam of a beam pair link that includes thereceive beam. The operations of block 1430 may be performed according tothe methods described herein. In certain examples, aspects of theoperations of block 1430 may be performed by a reference signal processmanager as described with reference to FIGS. 6 through 9. The UE, aspart of transmitting the measurement report, may transmit measurementsfrom reference signal processing such as channel state measurements,which may include energy measurements for a reference signal,interference and noise measurements, or any combination thereof. Thetransmit beam may use the resources that were configured for the slotand may be transmitted according to the beamforming parametersassociated with the reference signal process.

FIG. 15 shows a flowchart illustrating a method 1500 for referencesignal resource location techniques in wireless communications inaccordance with aspects of the present disclosure. The operations ofmethod 1500 may be implemented by a base station 105 or its componentsas described herein. For example, the operations of method 1500 may beperformed by a base station reference signal manager as described withreference to FIGS. 10 through 13. In some examples, a base station 105may execute a set of codes to control the functional elements of thedevice to perform the functions described below. Additionally oralternatively, the base station 105 may perform aspects of the functionsdescribed below using special-purpose hardware.

At block 1505 the base station 105 may configure a user equipment (UE)with a plurality of reference signal processes for receiving andprocessing one or more reference signals to be transmitted in one ormore slots of a plurality of slots, each slot of the plurality of slotshaving a corresponding reference signal process of the plurality ofreference signal processes based at least in part on a location of theslot. The operations of block 1505 may be performed according to themethods described herein. In certain examples, aspects of the operationsof block 1505 may be performed by a reference signal process manager asdescribed with reference to FIGS. 10 through 13. In some cases, thereference signal processes may include identification of time resources,frequency resources, or combinations thereof, which may be identifiedseparately for different slots within a radio frame, based on the numberof reference signal processes and a location of the particular slotwithin the radio frame. In some cases, a reference signal process numbermay be equal to the slot number within a radio frame modulo N, where Nis larger than the number of provisioned reference signal processes(e.g., N may be 4 or 8).

At block 1510 the base station 105 may transmit radio resource control(RRC) signaling with configuration information for the plurality ofreference signal processes to the UE. The operations of block 1510 maybe performed according to the methods described herein. In certainexamples, aspects of the operations of block 1510 may be performed by areference signal process manager as described with reference to FIGS. 10through 13. In some cases, the RRC signaling may provide a set ofavailable reference signal processes that may be used for referencesignal monitoring and related reporting at the UE. This allows the UE toprepare the RF hardware for the appropriate sequence of receive-beamsahead of time, while also providing a base station with flexibility forscheduling non-periodic reference signals within slots.

At block 1515 the base station 105 may determine that a reference signalis to be transmitted via a transmit beam in a first slot of theplurality of slots. The operations of block 1515 may be performedaccording to the methods described herein. In certain examples, aspectsof the operations of block 1515 may be performed by a resourceallocation component as described with reference to FIGS. 10 through 13.In some cases, the base station 105 may determine slots for referencesignal processes based on various factors, such as channel qualityaspects, timing since prior reference signal processes, or one or moreother factors. Such determination at the base station 105-b may allowthe base station to schedule non-periodic reference signaltransmissions, as periodic reference signal transmissions would bepreconfigured and transmitted without an indication of the presence ofabsence of a reference signal transmission.

At block 1520 the base station 105 may transmit a control signal in thefirst slot to indicate a presence of the reference signal in the firstslot. The operations of block 1520 may be performed according to themethods described herein. In certain examples, aspects of the operationsof block 1520 may be performed by a control signal identificationcomponent as described with reference to FIGS. 10 through 13. In somecases, the control signal may be a flag in DCI to indicate the presenceor absence of a reference signal transmission in the slot.

At block 1525 the base station 105 may transmit the reference signal inthe first slot. The operations of block 1525 may be performed accordingto the methods described herein. In certain examples, aspects of theoperations of block 1525 may be performed by a transmission beam manageras described with reference to FIGS. 10 through 13. Such a referencesignal transmission may use the resources that were configured for theslot and may be transmitted according to the beamforming parametersassociated with the reference signal process.

At optional block 1530 the base station 105 may receive, responsive tothe transmitting the non-periodic reference signal, a measurement reportfrom the UE via a receive beam of a beam pair link that includes thetransmit beam. The operations of block 1530 may be performed accordingto the methods described herein. In certain examples, aspects of theoperations of block 1530 may be performed by a transmission beam manageras described with reference to FIGS. 10 through 13. Such a measurementreport via the receive beam may use the resources that were configuredfor the slot and may be transmitted according to the beamformingparameters associated with the reference signal process.

It should be noted that the methods described above describe possibleimplementations, and that the operations and the steps may be rearrangedor otherwise modified and that other implementations are possible.Furthermore, aspects from two or more of the methods may be combined.

Techniques described herein may be used for various wirelesscommunications systems such as code division multiple access (CDMA),time division multiple access (TDMA), frequency division multiple access(FDMA), orthogonal frequency division multiple access (OFDMA), singlecarrier frequency division multiple access (SC-FDMA), and other systems.The terms “system” and “network” are often used interchangeably. A codedivision multiple access (CDMA) system may implement a radio technologysuch as CDMA2000, Universal Terrestrial Radio Access (UTRA), etc.CDMA2000 covers IS-2000, IS-95, and IS-856 standards. IS-2000 Releasesmay be commonly referred to as CDMA2000 1×, 1×, etc. IS-856 (TIA-856) iscommonly referred to as CDMA2000 1×EV-DO, High Rate Packet Data (HRPD),etc. UTRA includes Wideband CDMA (WCDMA) and other variants of CDMA. ATDMA system may implement a radio technology such as Global System forMobile Communications (GSM).

An OFDMA system may implement a radio technology such as Ultra MobileBroadband (UMB), Evolved UTRA (E-UTRA), Institute of Electrical andElectronics Engineers (IEEE) 802.11 (Wi-Fi), IEEE 802.16 (WiMAX), IEEE802.20, Flash-OFDM, etc. UTRA and E-UTRA are part of Universal MobileTelecommunications System (UMTS). LTE and LTE-A are releases of UMTSthat use E-UTRA. UTRA, E-UTRA, UMTS, LTE, LTE-A, NR, and GSM aredescribed in documents from the organization named “3rd GenerationPartnership Project” (3GPP). CDMA2000 and UMB are described in documentsfrom an organization named “3rd Generation Partnership Project 2”(3GPP2). The techniques described herein may be used for the systems andradio technologies mentioned above as well as other systems and radiotechnologies. While aspects of an LTE or an NR system may be describedfor purposes of example, and LTE or NR terminology may be used in muchof the description, the techniques described herein are applicablebeyond LTE or NR applications.

In LTE/LTE-A networks, including such networks described herein, theterm evolved node B (eNB) may be generally used to describe the basestations. The wireless communications system or systems described hereinmay include a heterogeneous LTE/LTE-A or NR network in which differenttypes of eNBs provide coverage for various geographical regions. Forexample, each eNB, next generation NodeB (gNB), or base station mayprovide communication coverage for a macro cell, a small cell, or othertypes of cell. The term “cell” may be used to describe a base station, acarrier or component carrier associated with a base station, or acoverage area (e.g., sector, etc.) of a carrier or base station,depending on context.

Base stations may include or may be referred to by those skilled in theart as a base transceiver station, a radio base station, an accesspoint, a radio transceiver, a NodeB, eNodeB (eNB), gNB, Home NodeB, aHome eNodeB, or some other suitable terminology. The geographic coveragearea for a base station may be divided into sectors making up only aportion of the coverage area. The wireless communications system orsystems described herein may include base stations of different types(e.g., macro or small cell base stations). The UEs described herein maybe able to communicate with various types of base stations and networkequipment including macro eNBs, small cell eNBs, gNBs, relay basestations, and the like. There may be overlapping geographic coverageareas for different technologies.

A macro cell generally covers a relatively large geographic area (e.g.,several kilometers in radius) and may allow unrestricted access by UEswith service subscriptions with the network provider. A small cell is alower-powered base station, as compared with a macro cell, that mayoperate in the same or different (e.g., licensed, unlicensed, etc.)frequency bands as macro cells. Small cells may include pico cells,femto cells, and micro cells according to various examples. A pico cell,for example, may cover a small geographic area and may allowunrestricted access by UEs with service subscriptions with the networkprovider. A femto cell may also cover a small geographic area (e.g., ahome) and may provide restricted access by UEs having an associationwith the femto cell (e.g., UEs in a closed subscriber group (CSG), UEsfor users in the home, and the like). An eNB for a macro cell may bereferred to as a macro eNB. An eNB for a small cell may be referred toas a small cell eNB, a pico eNB, a femto eNB, or a home eNB. An eNB maysupport one or multiple (e.g., two, three, four, and the like) cells(e.g., component carriers).

The wireless communications system or systems described herein maysupport synchronous or asynchronous operation. For synchronousoperation, the base stations may have similar frame timing, andtransmissions from different base stations may be approximately alignedin time. For asynchronous operation, the base stations may havedifferent frame timing, and transmissions from different base stationsmay not be aligned in time. The techniques described herein may be usedfor either synchronous or asynchronous operations.

The downlink transmissions described herein may also be called forwardlink transmissions while the uplink transmissions may also be calledreverse link transmissions. Each communication link describedherein—including, for example, wireless communication system 100 and 200of FIGS. 1 and 2—may include one or more carriers, where each carriermay be a signal made up of multiple sub-carriers (e.g., waveform signalsof different frequencies).

The description set forth herein, in connection with the appendeddrawings, describes example configurations and does not represent allthe examples that may be implemented or that are within the scope of theclaims. The term “exemplary” used herein means “serving as an example,instance, or illustration,” and not “preferred” or “advantageous overother examples.” The detailed description includes specific details forthe purpose of providing an understanding of the described techniques.These techniques, however, may be practiced without these specificdetails. In some instances, well-known structures and devices are shownin block diagram form in order to avoid obscuring the concepts of thedescribed examples.

In the appended figures, similar components or features may have thesame reference label. Further, various components of the same type maybe distinguished by following the reference label by a dash and a secondlabel that distinguishes among the similar components. If just the firstreference label is used in the specification, the description isapplicable to any one of the similar components having the same firstreference label irrespective of the second reference label.

Information and signals described herein may be represented using any ofa variety of different technologies and techniques. For example, data,instructions, commands, information, signals, bits, symbols, and chipsthat may be referenced throughout the above description may berepresented by voltages, currents, electromagnetic waves, magneticfields or particles, optical fields or particles, or any combinationthereof.

The various illustrative blocks and modules described in connection withthe disclosure herein may be implemented or performed with ageneral-purpose processor, a DSP, an ASIC, an FPGA or other programmablelogic device, discrete gate or transistor logic, discrete hardwarecomponents, or any combination thereof designed to perform the functionsdescribed herein. A general-purpose processor may be a microprocessor,but in the alternative, the processor may be any conventional processor,controller, microcontroller, or state machine. A processor may also beimplemented as a combination of computing devices (e.g., a combinationof a DSP and a microprocessor, multiple microprocessors, one or moremicroprocessors in conjunction with a DSP core, or any other suchconfiguration).

The functions described herein may be implemented in hardware, softwareexecuted by a processor, firmware, or any combination thereof. Ifimplemented in software executed by a processor, the functions may bestored on or transmitted over as one or more instructions or code on acomputer-readable medium. Other examples and implementations are withinthe scope of the disclosure and appended claims. For example, due to thenature of software, functions described above can be implemented usingsoftware executed by a processor, hardware, firmware, hardwiring, orcombinations of any of these. Features implementing functions may alsobe physically located at various positions, including being distributedsuch that portions of functions are implemented at different physicallocations. Also, as used herein, including in the claims, “or” as usedin a list of items (for example, a list of items prefaced by a phrasesuch as “at least one of” or “one or more of”) indicates an inclusivelist such that, for example, a list of at least one of A, B, or C meansA or B or C or AB or AC or BC or ABC (i.e., A and B and C). Also, asused herein, the phrase “based on” shall not be construed as a referenceto a closed set of conditions. For example, an exemplary step that isdescribed as “based on condition A” may be based on both a condition Aand a condition B without departing from the scope of the presentdisclosure. In other words, as used herein, the phrase “based on” shallbe construed in the same manner as the phrase “based at least in parton.”

Computer-readable media includes both non-transitory computer storagemedia and communication media including any medium that facilitatestransfer of a computer program from one place to another. Anon-transitory storage medium may be any available medium that can beaccessed by a general purpose or special purpose computer. By way ofexample, and not limitation, non-transitory computer-readable media maycomprise RAM, ROM, electrically erasable programmable read only memory(EEPROM), compact disk (CD) ROM or other optical disk storage, magneticdisk storage or other magnetic storage devices, or any othernon-transitory medium that can be used to carry or store desired programcode means in the form of instructions or data structures and that canbe accessed by a general-purpose or special-purpose computer, or ageneral-purpose or special-purpose processor. Also, any connection isproperly termed a computer-readable medium. For example, if the softwareis transmitted from a website, server, or other remote source using acoaxial cable, fiber optic cable, twisted pair, digital subscriber line(DSL), or wireless technologies such as infrared, radio, and microwave,then the coaxial cable, fiber optic cable, twisted pair, DSL, orwireless technologies such as infrared, radio, and microwave areincluded in the definition of medium. Disk and disc, as used herein,include CD, laser disc, optical disc, digital versatile disc (DVD),floppy disk and Blu-ray disc where disks usually reproduce datamagnetically, while discs reproduce data optically with lasers.Combinations of the above are also included within the scope ofcomputer-readable media.

The description herein is provided to enable a person skilled in the artto make or use the disclosure. Various modifications to the disclosurewill be readily apparent to those skilled in the art, and the genericprinciples defined herein may be applied to other variations withoutdeparting from the scope of the disclosure. Thus, the disclosure is notlimited to the examples and designs described herein, but is to beaccorded the broadest scope consistent with the principles and novelfeatures disclosed herein.

What is claimed is:
 1. A method for wireless communication at a userequipment (UE), comprising: identifying, for at least a first slot of aplurality of slots, a first beamforming parameter for receiving areference signal in the first slot, the first beamforming parameteridentified from a plurality of different beamforming parameters based atleast in part on a location of the first slot; receiving a controlsignal that indicates a presence of the reference signal in the firstslot; and receiving the reference signal in the first slot of theplurality of slots based at least in part on the control signal and thefirst beamforming parameter.
 2. The method of claim 1, wherein the firstbeamforming parameter of the plurality of different beamformingparameters is further identified based at least in part on a number ofthe plurality of different beamforming parameters.
 3. The method ofclaim 1, wherein: the reference signal is a non-periodic referencesignal for measurement of one or more channel conditions of a receivebeam that carries the reference signal.
 4. The method of claim 1,wherein: the first beamforming parameter is associated with one or moreof a time resource or frequency resource configured for transmission ofthe reference signal in the first slot.
 5. The method of claim 4,wherein: the first beamforming parameter is identified based at least inpart on a slot index of the first slot, a slot index of a slot carryingthe control signal, or any combinations thereof.
 6. The method of claim1, wherein: the control signal comprises an indication in downlinkcontrol information (DCI) for the at least one of the plurality ofslots.
 7. The method of claim 1, further comprising: receiving radioresource control (RRC) signaling with configuration information for theplurality of different beamforming parameters.
 8. A method for wirelesscommunication at a base station, comprising: configuring a userequipment (UE) with a plurality of different beamforming parameters forreceiving one or more reference signals to be transmitted in one or moreslots of a plurality of slots, wherein a first beamforming parameter ofat least a first slot of the plurality of slots is based at least inpart on a location of the first slot within the plurality of slots;transmitting a control signal to indicate a presence of a referencesignal in the first slot of the plurality of slots; and transmitting thereference signal using the first beamforming parameter in the firstslot.
 9. The method of claim 8, wherein the first beamforming parameterof the plurality of different beamforming parameters is identified basedat least in part on a number of the plurality of different beamformingparameters.
 10. The method of claim 8, wherein: the reference signal isa non-periodic reference signal for measurement at the UE of one or morechannel conditions of a beam that carries the reference signal.
 11. Themethod of claim 8, wherein: the first beamforming parameter isassociated with one or more of a time resource or frequency resourceconfigured for transmission of the reference signal in the first slot.12. The method of claim 11, wherein: the first beamforming parameter isidentified based at least in part on a slot index of the first slot, aslot index of a slot carrying the control signal, or any combinationsthereof.
 13. The method of claim 8, wherein: the control signal conveysdownlink control information (DCI) which indicates the presence of thereference signal in at least the first slot of the plurality of slots.14. The method of claim 8, wherein: the configuring comprisestransmitting radio resource control (RRC) signaling with configurationinformation for the plurality of different beamforming parameters. 15.An apparatus for wireless communication, comprising: means foridentifying, for at least a first slot of a plurality of slots, a firstbeamforming parameter for receiving a reference signal in the firstslot, the first beamforming parameter identified from a plurality ofdifferent beamforming parameters based at least in part on a location ofthe first slot; means for receiving a control signal that indicates apresence of the reference signal in the first slot; and means forreceiving the reference signal in the first slot of the plurality ofslots based at least in part on the control signal and the firstbeamforming parameter.
 16. The apparatus of claim 15, wherein: the firstbeamforming parameter is associated with one or more of a time resourceor frequency resource configured for transmission of the referencesignal in the first slot.
 17. The apparatus of claim 16, wherein: thefirst beamforming parameter is identified based at least in part on aslot index of the first slot, a slot index of a slot carrying thecontrol signal, or any combinations thereof.
 18. The apparatus of claim15, wherein: the control signal comprises an indication in downlinkcontrol information (DCI) for the at least one of the plurality ofslots.
 19. The apparatus of claim 15, further comprising: means forreceiving radio resource control (RRC) signaling with configurationinformation for the plurality of different beamforming parameters. 20.An apparatus for wireless communication, comprising: means forconfiguring a user equipment (UE) with a plurality of differentbeamforming parameters for receiving one or more reference signals to betransmitted in one or more slots of a plurality of slots, wherein afirst beamforming parameter of at least a first slot of the plurality ofslots is based at least in part on a location of the first slot withinthe plurality of slots; means for transmitting a control signal toindicate a presence of a reference signal in the first slot of theplurality of slots; and means for transmitting the reference signalusing the first beamforming parameter in the first slot.
 21. Theapparatus of claim 20, wherein: the first beamforming parameter isassociated with one or more of a time resource or frequency resourceconfigured for transmission of the reference signal in the first slot.22. The apparatus of claim 21, wherein: the first beamforming parameteris identified based at least in part on a slot index of the first slot,a slot index of a slot carrying the control signal, or any combinationsthereof.
 23. The apparatus of claim 20, wherein: the control signalconveys downlink control information (DCI) which indicates the presenceof the reference signal in at least the first slot of the plurality ofslots.
 24. The apparatus of claim 20, wherein: the means for configuringtransmits radio resource control (RRC) signaling with configurationinformation for the plurality of different beamforming parameters. 25.An apparatus for wireless communication, comprising: a processor; memoryin electronic communication with the processor; and instructions storedin the memory and operable, when executed by the processor, to cause theapparatus to: identify, for at least a first slot of a plurality ofslots, a first beamforming parameter for receiving a reference signal inthe first slot, the first beamforming parameter identified from aplurality of different beamforming parameters based at least in part ona location of the first slot; receive a control signal that indicates apresence of the reference signal in the first slot; and receive thereference signal in the first slot of the plurality of slots based atleast in part on the control signal and the first beamforming parameter.26. The apparatus of claim 25, wherein: the first beamforming parameteris associated with one or more of a time resource or frequency resourceconfigured for transmission of the reference signal in the first slot.27. The apparatus of claim 26, wherein: the first beamforming parameteris identified based at least in part on a slot index of the first slot,a slot index of a slot carrying the control signal, or any combinationsthereof.
 28. The apparatus of claim 25, wherein: the control signalcomprises an indication in downlink control information (DCI) within theat least one of the plurality of slots.
 29. The apparatus of claim 25,wherein the instructions further cause the apparatus to: receive radioresource control (RRC) signaling with configuration information for theplurality of different beamforming parameters.
 30. An apparatus forwireless communication, comprising: a processor; memory in electroniccommunication with the processor; and instructions stored in the memoryand operable, when executed by the processor, to cause the apparatus to:configure a user equipment (UE) with a plurality of differentbeamforming parameters for receiving one or more reference signals to betransmitted in one or more slots of a plurality of slots, wherein afirst beamforming parameter of at least a first slot of the plurality ofslots is based at least in part on a location of the first slot withinthe plurality of slots; transmit a control signal to indicate a presenceof a reference signal in the first slot of the plurality of slots; andtransmit the reference signal using the first beamforming parameter inthe first slot.
 31. The apparatus of claim 30, wherein: the firstbeamforming parameter is associated with one or more of a time resourceor frequency resource configured for transmission of the referencesignal in the first slot.
 32. The apparatus of claim 31, wherein: thefirst beamforming parameter is identified based at least in part on aslot index of the first slot, a slot index of a slot carrying thecontrol signal, or any combinations thereof.
 33. The apparatus of claim30, wherein: the control signal includes downlink control information(DCI) which indicates the presence of the reference signal for at leastthe first slot of the plurality of slots.
 34. The apparatus of claim 30,wherein instructions further cause the apparatus to: transmit radioresource control (RRC) signaling with configuration information for theplurality of different beamforming parameters.
 35. A non-transitorycomputer readable medium storing code for wireless communication, thecode comprising instructions executable by a processor to: identify, forat least a first slot of a plurality of slots, a first beamformingparameter for receiving a reference signal in the first slot, the firstbeamforming parameter identified from a plurality of differentbeamforming parameters based at least in part on a location of the firstslot; receive a control signal that indicates a presence of thereference signal in the first slot; and receive the reference signal inthe first slot of the plurality of slots based at least in part on thecontrol signal and the first beamforming parameter.
 36. A non-transitorycomputer readable medium storing code for wireless communication, thecode comprising instructions executable by a processor to: configure auser equipment (UE) with a plurality of different beamforming parametersfor receiving one or more reference signals to be transmitted in one ormore slots of a plurality of slots, wherein a first beamformingparameter of at least a first slot of the plurality of slots is based atleast in part on a location of the first slot within the plurality ofslots; transmit a control signal to indicate a presence of a referencesignal in the first slot of the plurality of slots; and transmit thereference signal using the first beamforming parameter in the firstslot.